One could argue the one lie by a public figure, given a large enough following, can translate into a lie repeated a billion times by main street users. It's certainly less probable when the lie is sourced in the other direction.

> Lets fact check "God exists".

Easy, it's the same answer as the opposite assertion:

Undetermined. This statement is not agreed upon and is an ongoing subject of debate among both experts and in popular culture.

Public figures speak with authority - and like it or not, most of the world’s population has an underdeveloped ability to think critically (it isn’t taught in schools because it “undermines parental authority”, apparently: https://www.reddit.com/r/politics/comments/vo26x/texas_gop_w... ).